Arc Flash Hazards in Mining Operations

CIM Montreal 2007
Abstract Mining operations require large and extensive electrical networks. Within the last 10 years, an electrical hazard called 'Arc Flash' has been identified as a separate electrical hazard from the well know electrical shock hazard.

Whereas electrical shock hazards occur when coming into direct contact with energized and exposed conductors, arc flash hazards are non contact hazards that occur when insulation breaks down in electrical or testing equipment.

The Canadian Electrical Code specifies that all work on electrical equipment be conducted on de-energized equipment. However, there are instances where workers are exposed to energized conductors when troubleshooting or testing equipment.

Over time, switching operations of breakers feeding large inductive loads such as motors cause a gradual breakdown in an insulation's dielectric strength. Once this breakdown occurs, an arc between phases or phase to ground occurs which can produce temperatures of up to 5000 degrees celcius as well as blast energy and schrapnel causing injury and death.

Recent statistics show that arc flash burn injuries occur about 3000 times a year in North America with about 10% of these resulting in death. In addition, the blast and ensuing fire damages expensive electrical equipment and causes millions of dollars of lost production.

There are techniques to mitigate this energy that are comparitively inexpensive when compared to the millions of dollars of losses that a severe arc flash event can cause a large industrial company. The first step is to conduct an arc flash analysis of your companies entire electrical system.

IEEE-1584 has spent extensive time to develop electrical equations that will estimate with a reasonable amout of accuracy, the potential arc flash energy that exists if such an event would occur. From theses studies, recommendations can be made to protect workers and equipment by reducing this energy potential and providing your electrical workers with the proper protective clothing developed especially for arc flash hazrads.

The following presentation will show actual arc flash events caught on camera and show how this catastrophic event can be reduced or eliminated by;

A. Conducting an arc flash analysis
B. Providing recommendations for mitigation
C. Providing proper protective clothing (PPE)
D. Electrical training and awareness for workers.
Keywords: Electrical Safety, Arc Flash, IEEE-1584, PPE
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